Pump jack



April 16, 1940y R. H. DEMMLER 2,197,018

PUMP JACK Filed Oct. 7, 1959 2 Sheets-Sheet 1 HU" ummm" I lkml .,lllllllml Nlp mi" u" lI It HUHHI www UIN4 INVENTOR ewa/PM mmf@ April 16, 1940 R. H. DEMMLER 2,197,018

PUMP JACK Filed Oct. 7, 1939 ZIShGStS-Sheet 2 "lill, /4 23 '1% Z4 i j .I 0 /I I I INVENTOR www; 4 mlm/f2 Patented Apr. 16, 194i) I UNITED 'STATES enservorties PUMP JACK y Rudolph H. Demmler, Colorado. Springs. Colo.`

Application October `'7,

. l 3- Claims. `'I'his invention relates to a power transmission mechanism for pumps more particularly to a .pump jack. In the usual vpump jack, the motor,

, l Windmill, or' other vpower operating device is'sub motor on the up stroke thereof.

Another object of the invention is to design aI spring balanced pump jackj'in such a way that the leverage against which the springs act will increase in effect as the springs decrease in effect so that the resultant power delivered to the pump I rod will be uniform at all positions thereof.'

A further objectr ofthe invention is to con struct a springbalanced pump jackyin which the spring action is adjustable as"` to angle of application so that the action of the' springs "can be balanced against load conditions.' l

vThere are other advantages to be vobtained from the use of this inventionwhic'h is designed for simplicity, economy, and efficiency. These 307Will become more apparent from the following detailed description.

In the' following detailed description 'of the -invention reference is had'to thel accompanying Fig. 3 is a plan View with the cover plate removed.

Fig. 4 is a vertical, longitudinal section, taken on the line 4 4, Fig. 1.

Fig. 5 is a detail section taken on the line 5 5, Fig. 4.

The invention is preferably designed to be secured to the upper extremity of the pump casing of a well. In the drawings, the well casing is in- 50 dicated at II) and the pump rod `therein at II.

The mechanism is enclosed in a gear case I2 covered by means of a aniitablecovei` I3. The case I2 is oil tight and is maintained partially filled with lubricating oil, as indicated at I4. 55 lI ihe oase is formed with an internal, vertical 1939, seria; No. 298,381' (o1. 74.448)

sleeve I5 about-the pump rod il to lprevent the.

oil from flowing into the casing II). L #A power shaft I3 extends into the case I2 `through a suitable packed outboard bearing I 1.

'lheother extremity of the shaft I3 is supported l in a 'stop bearing I8 secured to the case i2 by means of a'iiange I9. A power pinion2 is keyed or otherwise secured on ythe power shaft I6 and l` meshes'with a crank gear- 2l which is journalled on a stub shaft 22 within the case I2. The gear 2| lcarried acrank pin'23 surrounded by ball bearings 24.l

The crank pin and its. bearings ridein 'a guid slot 25 in a pumping lever 26. Abell' crank 21 l'"projects from the .lever 26. The lever is mounted on a hinge shaft 28 at the point of intersecn shaft is carried in suitable bearing blocks 29 in the caseand access thereto is obtained through a plug 3E) in theside of the oase. `The other `extremity of lthel pump lever terminates in a hook 3I which. is positioned so that it may extend into th-e sleeve I5 where itis connected by means vof a suitablepin 32 to the pump rod II. It can be readily seen thatv asthe gear2l rotates, the lever 25' will be o scillated tove'rtically reciprocate the pump-rod II.`

A pair of spring rods 33 are threaded into head's`34 which are pivotally mounted on a pivot pin35"at"e"ach sid'eof the bell crank lever21. The free extremities of the rods 33 pass through an' abutment 'arm 33 formed integrally with the Acase vI2 and extending'l upwardly therefrom atan angle to: positionits face substantially at right angles totheaxis of the rods 33.

The abutment arm 38 contains 'vertical slots 3'I for receiving theI extremities of the spring rods 33. The siots allow the angle of the rods tobe changed as desired. Each rod is held at any pre. determined angle by means of a washer 38 which tations 39 in the arm 3E by means of a compressing spring 40. The springs It surround the rods 33 and each is compressed thereon between one ofthe washers 38 and a spring adjusting nut 4I. The spring adjusting nut II is locked on the rod by means of a jam nut 42 andthe rods are` locked in the heads 34 by means of similar jam nuts 43.

It is desired to call particular attention to the angular placement of the spring rodsv 33. This placement is such as to assist the gear 2l in exact proportion as this assistance is required, and so as to deliver a uniform thrust from the springs.

Let us assume that the device is in the position tion of the bell crank 21 therewith. The hinge l 40 is forced into one of a series of receiving indenshown in Fig. 4 ready to start the "up stroke of the pump rod Il.` At this point the Work is exceedingly diificult since the rod must be started upward under its weight and the weight of the Water being lifted. The position of the crank pin 23 isvsuch, however, that. it obtains an advantageous leverage on the pump lever 26 as the crank pin moves from its low point. At this point the springs 40 are at their greatest compression and will exert their maximum push. They are acting, however, at an'obtuse angle to. the levers'Z'l so that they are not 'exerting their maximum torque on the pump lever 26. As the crank 23 rises, however, its lever arm increases and the load thereon proportionately increases. The leverage of the bell crank lever 21 has also increased since it has moved to a position at right anglesto the thrust of the'y springs so `asf-to deliver a maximum effect from the expansion there-- of. The above construction causes resultant reaching of the springs to be uniformifrom the beginning of the up, strokeguntilwell toward the end thereof at which time the leverageof the crank increases t0 take over the load.

On the down stroke, the entire motor power and the Weight of the pump rod is absorbed in the compression of these springs. The device therefore acts to place a uniform load on theA mo- 1 tor and to cut the power required substantially 30 i ment necessary. The abutment arm also serves to hold the cover I3 in place, there being a cap screw i4 threaded therein for this purpose. The

i cover is sealed to the case by means of suitable v electric motor, etc.

While a specific form of the improvementl has been described and illustrated herein', it is der sired to be understood that the same may be varied, within .the scope of-l the appended claims, without departing from the spirit of the invention. f

Having thus describedthe invention, what is claimed Aand desired secured' 'by Lettersn Patent is:

1. A spring balanced power' transmission unit for pumps comprising: a rotating crankmember; a pump lever. hinged at its one extremity` so as to lie in a plan parallel toz-said crank member;

means for attaching a pump rod to the other will reciprocate the latter;` means for attaching.y

the other extremity of said lever to a pump rod; a` bell crank lever projecting fromsaid pump lever adjacent itsy pivot point; and a compres-4 sion spring acting againstsail bell crank ever, said compression spring being so positioned that the angle between its axis .and the axisjiof the bell crank lever will be substantially v90"` at thev time the crank pin has completed one-half of its y up stroke.

2. A spring balanced power transmission unit l 15 a pump lever hinged at its one extremity so asto lie in aplanparallel' to said crank member; means` for attaching a pump rod to the other extremity of said lever; a crank projecting from said crank v forrpumps comprising: a rotating crank member;

member'into a longitudinal slot in said pump lever so that rotation of the former will reciprocate the latter; means for attaching the other extremity of said lever to a pumpv rod; abell crank lever projecting from said pump lever ad-x: jacent its pivot point; a hinge pin extending' throughsaid bell crank lever;Y a spring rod ateach side of said leverhinged on said pivot pin; an

abutment member through which the other extremities of said spring rods pass; and spring i surrounding each rod, said springsbeing compressed between said abutment member and adjusting nuts on said rods. f i

3. A spring balanced power transmission unit for pumps comprising: ra rotating crank meinber; a pump lever hinged at its one extremity I so as to lie in a plan parallel to said crank member means for attaching a pump rod to the other extremity of-.said lever; a crank projecting from saidA crank member into a longitudinal sloty insaid pump lever so that rotation of the former will reciprocate the latter; means for attaching thevother extremity of said/lever to a pumpA rod; abell crank lever projecting from said pump lever adjacent itspivot point; a hinge pin extending through said bell crank. lever; `a spring rod at each side or said lever.l hinged on said pivot pin; an abutment member through which the other extremities ofsaid spring rods pass; spring surrounding each rod, said springs` being 

